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Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl 

Pull sysctl updates from Eric Biederman:

 - Rewrite of sysctl for speed and clarity.

   Insert/remove/Lookup in sysctl are all now O(NlogN) operations, and
   are no longer bottlenecks in the process of adding and removing
   network devices.

   sysctl is now focused on being a filesystem instead of system call
   and the code can all be found in fs/proc/proc_sysctl.c.  Hopefully
   this means the code is now approachable.

   Much thanks is owed to Lucian Grinjincu for keeping at this until
   something was found that was usable.

 - The recent proc_sys_poll oops found by the fuzzer during hibernation
   is fixed.

* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl: (36 commits)
  sysctl: protect poll() in entries that may go away
  sysctl: Don't call sysctl_follow_link unless we are a link.
  sysctl: Comments to make the code clearer.
  sysctl: Correct error return from get_subdir
  sysctl: An easier to read version of find_subdir
  sysctl: fix memset parameters in setup_sysctl_set()
  sysctl: remove an unused variable
  sysctl: Add register_sysctl for normal sysctl users
  sysctl: Index sysctl directories with rbtrees.
  sysctl: Make the header lists per directory.
  sysctl: Move sysctl_check_dups into insert_header
  sysctl: Modify __register_sysctl_paths to take a set instead of a root and an nsproxy
  sysctl: Replace root_list with links between sysctl_table_sets.
  sysctl: Add sysctl_print_dir and use it in get_subdir
  sysctl: Stop requiring explicit management of sysctl directories
  sysctl: Add a root pointer to ctl_table_set
  sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry
  sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry.
  sysctl: Normalize the root_table data structure.
  sysctl: Factor out insert_header and erase_header
  ...
This commit is contained in:
Linus Torvalds 2012-03-23 18:08:58 -07:00
Родитель dae430c6f6 4e474a00d7
Коммит f1d38e423a
8 изменённых файлов: 1280 добавлений и 797 удалений
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3
fs/proc/internal.h
Просмотреть файл

@ -10,12 +10,15 @@
*/
#include <linux/proc_fs.h>
struct ctl_table_header;
extern struct proc_dir_entry proc_root;
#ifdef CONFIG_PROC_SYSCTL
extern int proc_sys_init(void);
extern void sysctl_head_put(struct ctl_table_header *head);
#else
static inline void proc_sys_init(void) { }
static inline void sysctl_head_put(struct ctl_table_header *head) { }
#endif
#ifdef CONFIG_NET
extern int proc_net_init(void);

1274
fs/proc/proc_sysctl.c
Просмотреть файл

Разница между файлами не показана из-за своего большого размера Загрузить разницу

106
include/linux/sysctl.h
Просмотреть файл

@ -932,34 +932,14 @@ enum
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/wait.h>
#include <linux/rbtree.h>
/* For the /proc/sys support */
struct ctl_table;
struct nsproxy;
struct ctl_table_root;
struct ctl_table_set {
struct list_head list;
struct ctl_table_set *parent;
int (*is_seen)(struct ctl_table_set *);
};
extern void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_set *parent,
int (*is_seen)(struct ctl_table_set *));
struct ctl_table_header;
extern void sysctl_head_get(struct ctl_table_header *);
extern void sysctl_head_put(struct ctl_table_header *);
extern int sysctl_is_seen(struct ctl_table_header *);
extern struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *);
extern struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev);
extern struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
struct ctl_table_header *prev);
extern void sysctl_head_finish(struct ctl_table_header *prev);
extern int sysctl_perm(struct ctl_table_root *root,
struct ctl_table *table, int op);
struct ctl_dir;
typedef struct ctl_table ctl_table;
@ -1023,8 +1003,6 @@ static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
return (void *)(unsigned long)atomic_read(&poll->event);
}
void proc_sys_poll_notify(struct ctl_table_poll *poll);
#define __CTL_TABLE_POLL_INITIALIZER(name) { \
.event = ATOMIC_INIT(0), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
@ -1039,21 +1017,16 @@ struct ctl_table
void *data;
int maxlen;
umode_t mode;
struct ctl_table *child;
struct ctl_table *parent; /* Automatically set */
struct ctl_table *child; /* Deprecated */
proc_handler *proc_handler; /* Callback for text formatting */
struct ctl_table_poll *poll;
void *extra1;
void *extra2;
};
struct ctl_table_root {
struct list_head root_list;
struct ctl_table_set default_set;
struct ctl_table_set *(*lookup)(struct ctl_table_root *root,
struct nsproxy *namespaces);
int (*permissions)(struct ctl_table_root *root,
struct nsproxy *namespaces, struct ctl_table *table);
struct ctl_node {
struct rb_node node;
struct ctl_table_header *header;
};
/* struct ctl_table_header is used to maintain dynamic lists of
@ -1063,9 +1036,9 @@ struct ctl_table_header
union {
struct {
struct ctl_table *ctl_table;
struct list_head ctl_entry;
int used;
int count;
int nreg;
};
struct rcu_head rcu;
};
@ -1073,9 +1046,27 @@ struct ctl_table_header
struct ctl_table *ctl_table_arg;
struct ctl_table_root *root;
struct ctl_table_set *set;
struct ctl_table *attached_by;
struct ctl_table *attached_to;
struct ctl_table_header *parent;
struct ctl_dir *parent;
struct ctl_node *node;
};
struct ctl_dir {
/* Header must be at the start of ctl_dir */
struct ctl_table_header header;
struct rb_root root;
};
struct ctl_table_set {
int (*is_seen)(struct ctl_table_set *);
struct ctl_dir dir;
};
struct ctl_table_root {
struct ctl_table_set default_set;
struct ctl_table_set *(*lookup)(struct ctl_table_root *root,
struct nsproxy *namespaces);
int (*permissions)(struct ctl_table_root *root,
struct nsproxy *namespaces, struct ctl_table *table);
};
/* struct ctl_path describes where in the hierarchy a table is added */
@ -1083,16 +1074,53 @@ struct ctl_path {
const char *procname;
};
#ifdef CONFIG_SYSCTL
void proc_sys_poll_notify(struct ctl_table_poll *poll);
extern void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_root *root,
int (*is_seen)(struct ctl_table_set *));
extern void retire_sysctl_set(struct ctl_table_set *set);
void register_sysctl_root(struct ctl_table_root *root);
struct ctl_table_header *__register_sysctl_table(
struct ctl_table_set *set,
const char *path, struct ctl_table *table);
struct ctl_table_header *__register_sysctl_paths(
struct ctl_table_root *root, struct nsproxy *namespaces,
struct ctl_table_set *set,
const struct ctl_path *path, struct ctl_table *table);
struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
struct ctl_table *table);
void unregister_sysctl_table(struct ctl_table_header * table);
int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table);
extern int sysctl_init(void);
#else /* CONFIG_SYSCTL */
static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
{
return NULL;
}
static inline struct ctl_table_header *register_sysctl_paths(
const struct ctl_path *path, struct ctl_table *table)
{
return NULL;
}
static inline void unregister_sysctl_table(struct ctl_table_header * table)
{
}
static inline void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_root *root,
int (*is_seen)(struct ctl_table_set *))
{
}
#endif /* CONFIG_SYSCTL */
#endif /* __KERNEL__ */

1
kernel/Makefile
Просмотреть файл

@ -27,7 +27,6 @@ obj-y += power/
obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_SYSCTL_SYSCALL_CHECK) += sysctl_check.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o

501
kernel/sysctl.c
Просмотреть файл

@ -193,20 +193,6 @@ static int sysrq_sysctl_handler(ctl_table *table, int write,
#endif
static struct ctl_table root_table[];
static struct ctl_table_root sysctl_table_root;
static struct ctl_table_header root_table_header = {
{{.count = 1,
.ctl_table = root_table,
.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
.root = &sysctl_table_root,
.set = &sysctl_table_root.default_set,
};
static struct ctl_table_root sysctl_table_root = {
.root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
.default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
};
static struct ctl_table kern_table[];
static struct ctl_table vm_table[];
static struct ctl_table fs_table[];
@ -223,7 +209,7 @@ int sysctl_legacy_va_layout;
/* The default sysctl tables: */
static struct ctl_table root_table[] = {
static struct ctl_table sysctl_base_table[] = {
{
.procname = "kernel",
.mode = 0555,
@ -1560,490 +1546,12 @@ static struct ctl_table dev_table[] = {
{ }
};
static DEFINE_SPINLOCK(sysctl_lock);
/* called under sysctl_lock */
static int use_table(struct ctl_table_header *p)
int __init sysctl_init(void)
{
if (unlikely(p->unregistering))
return 0;
p->used++;
return 1;
}
/* called under sysctl_lock */
static void unuse_table(struct ctl_table_header *p)
{
if (!--p->used)
if (unlikely(p->unregistering))
complete(p->unregistering);
}
/* called under sysctl_lock, will reacquire if has to wait */
static void start_unregistering(struct ctl_table_header *p)
{
/*
* if p->used is 0, nobody will ever touch that entry again;
* we'll eliminate all paths to it before dropping sysctl_lock
*/
if (unlikely(p->used)) {
struct completion wait;
init_completion(&wait);
p->unregistering = &wait;
spin_unlock(&sysctl_lock);
wait_for_completion(&wait);
spin_lock(&sysctl_lock);
} else {
/* anything non-NULL; we'll never dereference it */
p->unregistering = ERR_PTR(-EINVAL);
}
/*
* do not remove from the list until nobody holds it; walking the
* list in do_sysctl() relies on that.
*/
list_del_init(&p->ctl_entry);
}
void sysctl_head_get(struct ctl_table_header *head)
{
spin_lock(&sysctl_lock);
head->count++;
spin_unlock(&sysctl_lock);
}
void sysctl_head_put(struct ctl_table_header *head)
{
spin_lock(&sysctl_lock);
if (!--head->count)
kfree_rcu(head, rcu);
spin_unlock(&sysctl_lock);
}
struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
{
if (!head)
BUG();
spin_lock(&sysctl_lock);
if (!use_table(head))
head = ERR_PTR(-ENOENT);
spin_unlock(&sysctl_lock);
return head;
}
void sysctl_head_finish(struct ctl_table_header *head)
{
if (!head)
return;
spin_lock(&sysctl_lock);
unuse_table(head);
spin_unlock(&sysctl_lock);
}
static struct ctl_table_set *
lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
{
struct ctl_table_set *set = &root->default_set;
if (root->lookup)
set = root->lookup(root, namespaces);
return set;
}
static struct list_head *
lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
{
struct ctl_table_set *set = lookup_header_set(root, namespaces);
return &set->list;
}
struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
struct ctl_table_header *prev)
{
struct ctl_table_root *root;
struct list_head *header_list;
struct ctl_table_header *head;
struct list_head *tmp;
spin_lock(&sysctl_lock);
if (prev) {
head = prev;
tmp = &prev->ctl_entry;
unuse_table(prev);
goto next;
}
tmp = &root_table_header.ctl_entry;
for (;;) {
head = list_entry(tmp, struct ctl_table_header, ctl_entry);
if (!use_table(head))
goto next;
spin_unlock(&sysctl_lock);
return head;
next:
root = head->root;
tmp = tmp->next;
header_list = lookup_header_list(root, namespaces);
if (tmp != header_list)
continue;
do {
root = list_entry(root->root_list.next,
struct ctl_table_root, root_list);
if (root == &sysctl_table_root)
goto out;
header_list = lookup_header_list(root, namespaces);
} while (list_empty(header_list));
tmp = header_list->next;
}
out:
spin_unlock(&sysctl_lock);
return NULL;
}
struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
{
return __sysctl_head_next(current->nsproxy, prev);
}
void register_sysctl_root(struct ctl_table_root *root)
{
spin_lock(&sysctl_lock);
list_add_tail(&root->root_list, &sysctl_table_root.root_list);
spin_unlock(&sysctl_lock);
}
/*
* sysctl_perm does NOT grant the superuser all rights automatically, because
* some sysctl variables are readonly even to root.
*/
static int test_perm(int mode, int op)
{
if (!current_euid())
mode >>= 6;
else if (in_egroup_p(0))
mode >>= 3;
if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
return 0;
return -EACCES;
}
int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
{
int mode;
if (root->permissions)
mode = root->permissions(root, current->nsproxy, table);
else
mode = table->mode;
return test_perm(mode, op);
}
static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
{
for (; table->procname; table++) {
table->parent = parent;
if (table->child)
sysctl_set_parent(table, table->child);
}
}
static __init int sysctl_init(void)
{
sysctl_set_parent(NULL, root_table);
#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
sysctl_check_table(current->nsproxy, root_table);
#endif
register_sysctl_table(sysctl_base_table);
return 0;
}
core_initcall(sysctl_init);
static struct ctl_table *is_branch_in(struct ctl_table *branch,
struct ctl_table *table)
{
struct ctl_table *p;
const char *s = branch->procname;
/* branch should have named subdirectory as its first element */
if (!s || !branch->child)
return NULL;
/* ... and nothing else */
if (branch[1].procname)
return NULL;
/* table should contain subdirectory with the same name */
for (p = table; p->procname; p++) {
if (!p->child)
continue;
if (p->procname && strcmp(p->procname, s) == 0)
return p;
}
return NULL;
}
/* see if attaching q to p would be an improvement */
static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
{
struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
struct ctl_table *next;
int is_better = 0;
int not_in_parent = !p->attached_by;
while ((next = is_branch_in(by, to)) != NULL) {
if (by == q->attached_by)
is_better = 1;
if (to == p->attached_by)
not_in_parent = 1;
by = by->child;
to = next->child;
}
if (is_better && not_in_parent) {
q->attached_by = by;
q->attached_to = to;
q->parent = p;
}
}
/**
* __register_sysctl_paths - register a sysctl hierarchy
* @root: List of sysctl headers to register on
* @namespaces: Data to compute which lists of sysctl entries are visible
* @path: The path to the directory the sysctl table is in.
* @table: the top-level table structure
*
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
* array. A completely 0 filled entry terminates the table.
*
* The members of the &struct ctl_table structure are used as follows:
*
* procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
* enter a sysctl file
*
* data - a pointer to data for use by proc_handler
*
* maxlen - the maximum size in bytes of the data
*
* mode - the file permissions for the /proc/sys file, and for sysctl(2)
*
* child - a pointer to the child sysctl table if this entry is a directory, or
* %NULL.
*
* proc_handler - the text handler routine (described below)
*
* de - for internal use by the sysctl routines
*
* extra1, extra2 - extra pointers usable by the proc handler routines
*
* Leaf nodes in the sysctl tree will be represented by a single file
* under /proc; non-leaf nodes will be represented by directories.
*
* sysctl(2) can automatically manage read and write requests through
* the sysctl table. The data and maxlen fields of the ctl_table
* struct enable minimal validation of the values being written to be
* performed, and the mode field allows minimal authentication.
*
* There must be a proc_handler routine for any terminal nodes
* mirrored under /proc/sys (non-terminals are handled by a built-in
* directory handler). Several default handlers are available to
* cover common cases -
*
* proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
* proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
* proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
*
* It is the handler's job to read the input buffer from user memory
* and process it. The handler should return 0 on success.
*
* This routine returns %NULL on a failure to register, and a pointer
* to the table header on success.
*/
struct ctl_table_header *__register_sysctl_paths(
struct ctl_table_root *root,
struct nsproxy *namespaces,
const struct ctl_path *path, struct ctl_table *table)
{
struct ctl_table_header *header;
struct ctl_table *new, **prevp;
unsigned int n, npath;
struct ctl_table_set *set;
/* Count the path components */
for (npath = 0; path[npath].procname; ++npath)
;
/*
* For each path component, allocate a 2-element ctl_table array.
* The first array element will be filled with the sysctl entry
* for this, the second will be the sentinel (procname == 0).
*
* We allocate everything in one go so that we don't have to
* worry about freeing additional memory in unregister_sysctl_table.
*/
header = kzalloc(sizeof(struct ctl_table_header) +
(2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
if (!header)
return NULL;
new = (struct ctl_table *) (header + 1);
/* Now connect the dots */
prevp = &header->ctl_table;
for (n = 0; n < npath; ++n, ++path) {
/* Copy the procname */
new->procname = path->procname;
new->mode = 0555;
*prevp = new;
prevp = &new->child;
new += 2;
}
*prevp = table;
header->ctl_table_arg = table;
INIT_LIST_HEAD(&header->ctl_entry);
header->used = 0;
header->unregistering = NULL;
header->root = root;
sysctl_set_parent(NULL, header->ctl_table);
header->count = 1;
#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
if (sysctl_check_table(namespaces, header->ctl_table)) {
kfree(header);
return NULL;
}
#endif
spin_lock(&sysctl_lock);
header->set = lookup_header_set(root, namespaces);
header->attached_by = header->ctl_table;
header->attached_to = root_table;
header->parent = &root_table_header;
for (set = header->set; set; set = set->parent) {
struct ctl_table_header *p;
list_for_each_entry(p, &set->list, ctl_entry) {
if (p->unregistering)
continue;
try_attach(p, header);
}
}
header->parent->count++;
list_add_tail(&header->ctl_entry, &header->set->list);
spin_unlock(&sysctl_lock);
return header;
}
/**
* register_sysctl_table_path - register a sysctl table hierarchy
* @path: The path to the directory the sysctl table is in.
* @table: the top-level table structure
*
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
* array. A completely 0 filled entry terminates the table.
*
* See __register_sysctl_paths for more details.
*/
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
struct ctl_table *table)
{
return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
path, table);
}
/**
* register_sysctl_table - register a sysctl table hierarchy
* @table: the top-level table structure
*
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
* array. A completely 0 filled entry terminates the table.
*
* See register_sysctl_paths for more details.
*/
struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
{
static const struct ctl_path null_path[] = { {} };
return register_sysctl_paths(null_path, table);
}
/**
* unregister_sysctl_table - unregister a sysctl table hierarchy
* @header: the header returned from register_sysctl_table
*
* Unregisters the sysctl table and all children. proc entries may not
* actually be removed until they are no longer used by anyone.
*/
void unregister_sysctl_table(struct ctl_table_header * header)
{
might_sleep();
if (header == NULL)
return;
spin_lock(&sysctl_lock);
start_unregistering(header);
if (!--header->parent->count) {
WARN_ON(1);
kfree_rcu(header->parent, rcu);
}
if (!--header->count)
kfree_rcu(header, rcu);
spin_unlock(&sysctl_lock);
}
int sysctl_is_seen(struct ctl_table_header *p)
{
struct ctl_table_set *set = p->set;
int res;
spin_lock(&sysctl_lock);
if (p->unregistering)
res = 0;
else if (!set->is_seen)
res = 1;
else
res = set->is_seen(set);
spin_unlock(&sysctl_lock);
return res;
}
void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_set *parent,
int (*is_seen)(struct ctl_table_set *))
{
INIT_LIST_HEAD(&p->list);
p->parent = parent ? parent : &sysctl_table_root.default_set;
p->is_seen = is_seen;
}
#else /* !CONFIG_SYSCTL */
struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
{
return NULL;
}
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
struct ctl_table *table)
{
return NULL;
}
void unregister_sysctl_table(struct ctl_table_header * table)
{
}
void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_set *parent,
int (*is_seen)(struct ctl_table_set *))
{
}
void sysctl_head_put(struct ctl_table_header *head)
{
}
#endif /* CONFIG_SYSCTL */
/*
@ -3009,6 +2517,3 @@ EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
EXPORT_SYMBOL(proc_dostring);
EXPORT_SYMBOL(proc_doulongvec_minmax);
EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
EXPORT_SYMBOL(register_sysctl_table);
EXPORT_SYMBOL(register_sysctl_paths);
EXPORT_SYMBOL(unregister_sysctl_table);

160
kernel/sysctl_check.c
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@ -1,160 +0,0 @@
#include <linux/stat.h>
#include <linux/sysctl.h>
#include "../fs/xfs/xfs_sysctl.h"
#include <linux/sunrpc/debug.h>
#include <linux/string.h>
#include <net/ip_vs.h>
static int sysctl_depth(struct ctl_table *table)
{
struct ctl_table *tmp;
int depth;
depth = 0;
for (tmp = table; tmp->parent; tmp = tmp->parent)
depth++;
return depth;
}
static struct ctl_table *sysctl_parent(struct ctl_table *table, int n)
{
int i;
for (i = 0; table && i < n; i++)
table = table->parent;
return table;
}
static void sysctl_print_path(struct ctl_table *table)
{
struct ctl_table *tmp;
int depth, i;
depth = sysctl_depth(table);
if (table->procname) {
for (i = depth; i >= 0; i--) {
tmp = sysctl_parent(table, i);
printk("/%s", tmp->procname?tmp->procname:"");
}
}
printk(" ");
}
static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces,
struct ctl_table *table)
{
struct ctl_table_header *head;
struct ctl_table *ref, *test;
int depth, cur_depth;
depth = sysctl_depth(table);
for (head = __sysctl_head_next(namespaces, NULL); head;
head = __sysctl_head_next(namespaces, head)) {
cur_depth = depth;
ref = head->ctl_table;
repeat:
test = sysctl_parent(table, cur_depth);
for (; ref->procname; ref++) {
int match = 0;
if (cur_depth && !ref->child)
continue;
if (test->procname && ref->procname &&
(strcmp(test->procname, ref->procname) == 0))
match++;
if (match) {
if (cur_depth != 0) {
cur_depth--;
ref = ref->child;
goto repeat;
}
goto out;
}
}
}
ref = NULL;
out:
sysctl_head_finish(head);
return ref;
}
static void set_fail(const char **fail, struct ctl_table *table, const char *str)
{
if (*fail) {
printk(KERN_ERR "sysctl table check failed: ");
sysctl_print_path(table);
printk(" %s\n", *fail);
dump_stack();
}
*fail = str;
}
static void sysctl_check_leaf(struct nsproxy *namespaces,
struct ctl_table *table, const char **fail)
{
struct ctl_table *ref;
ref = sysctl_check_lookup(namespaces, table);
if (ref && (ref != table))
set_fail(fail, table, "Sysctl already exists");
}
int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table)
{
int error = 0;
for (; table->procname; table++) {
const char *fail = NULL;
if (table->parent) {
if (!table->parent->procname)
set_fail(&fail, table, "Parent without procname");
}
if (table->child) {
if (table->data)
set_fail(&fail, table, "Directory with data?");
if (table->maxlen)
set_fail(&fail, table, "Directory with maxlen?");
if ((table->mode & (S_IRUGO|S_IXUGO)) != table->mode)
set_fail(&fail, table, "Writable sysctl directory");
if (table->proc_handler)
set_fail(&fail, table, "Directory with proc_handler");
if (table->extra1)
set_fail(&fail, table, "Directory with extra1");
if (table->extra2)
set_fail(&fail, table, "Directory with extra2");
} else {
if ((table->proc_handler == proc_dostring) ||
(table->proc_handler == proc_dointvec) ||
(table->proc_handler == proc_dointvec_minmax) ||
(table->proc_handler == proc_dointvec_jiffies) ||
(table->proc_handler == proc_dointvec_userhz_jiffies) ||
(table->proc_handler == proc_dointvec_ms_jiffies) ||
(table->proc_handler == proc_doulongvec_minmax) ||
(table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
if (!table->data)
set_fail(&fail, table, "No data");
if (!table->maxlen)
set_fail(&fail, table, "No maxlen");
}
#ifdef CONFIG_PROC_SYSCTL
if (!table->proc_handler)
set_fail(&fail, table, "No proc_handler");
#endif
sysctl_check_leaf(namespaces, table, &fail);
}
if (table->mode > 0777)
set_fail(&fail, table, "bogus .mode");
if (fail) {
set_fail(&fail, table, NULL);
error = -EINVAL;
}
if (table->child)
error |= sysctl_check_table(namespaces, table->child);
}
return error;
}

8
lib/Kconfig.debug
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@ -1141,14 +1141,6 @@ config LATENCYTOP
Enable this option if you want to use the LatencyTOP tool
to find out which userspace is blocking on what kernel operations.
config SYSCTL_SYSCALL_CHECK
bool "Sysctl checks"
depends on SYSCTL
---help---
sys_sysctl uses binary paths that have been found challenging
to properly maintain and use. This enables checks that help
you to keep things correct.
source mm/Kconfig.debug
source kernel/trace/Kconfig

24
net/sysctl_net.c
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@ -74,15 +74,13 @@ static struct ctl_table_root net_sysctl_ro_root = {
static int __net_init sysctl_net_init(struct net *net)
{
setup_sysctl_set(&net->sysctls,
&net_sysctl_ro_root.default_set,
is_seen);
setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
return 0;
}
static void __net_exit sysctl_net_exit(struct net *net)
{
WARN_ON(!list_empty(&net->sysctls.list));
retire_sysctl_set(&net->sysctls);
}
static struct pernet_operations sysctl_pernet_ops = {
@ -90,36 +88,32 @@ static struct pernet_operations sysctl_pernet_ops = {
.exit = sysctl_net_exit,
};
static __init int sysctl_init(void)
static __init int net_sysctl_init(void)
{
int ret;
ret = register_pernet_subsys(&sysctl_pernet_ops);
if (ret)
goto out;
register_sysctl_root(&net_sysctl_root);
setup_sysctl_set(&net_sysctl_ro_root.default_set, NULL, NULL);
setup_sysctl_set(&net_sysctl_ro_root.default_set, &net_sysctl_ro_root, NULL);
register_sysctl_root(&net_sysctl_ro_root);
register_sysctl_root(&net_sysctl_root);
out:
return ret;
}
subsys_initcall(sysctl_init);
subsys_initcall(net_sysctl_init);
struct ctl_table_header *register_net_sysctl_table(struct net *net,
const struct ctl_path *path, struct ctl_table *table)
{
struct nsproxy namespaces;
namespaces = *current->nsproxy;
namespaces.net_ns = net;
return __register_sysctl_paths(&net_sysctl_root,
&namespaces, path, table);
return __register_sysctl_paths(&net->sysctls, path, table);
}
EXPORT_SYMBOL_GPL(register_net_sysctl_table);
struct ctl_table_header *register_net_sysctl_rotable(const
struct ctl_path *path, struct ctl_table *table)
{
return __register_sysctl_paths(&net_sysctl_ro_root,
&init_nsproxy, path, table);
return __register_sysctl_paths(&net_sysctl_ro_root.default_set,
path, table);
}
EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);